Light emitting device and method of manufacturing same

ABSTRACT

A light emitting device including a light emitting element, a light transmissive member, a light guide member, and a light reflective member. The light transmissive member is disposed on an upper surface of the light emitting element, and has a lower surface including a first region facing the light emitting element and a second region positioned outside of the first region. The light guide member covers a lateral surface of the light emitting element and the second region of the lower surface of the light transmissive member. The light reflective member covers the light emitting element, an upper surface of the light transmissive member and the light guide member. One of lateral surfaces of the light transmissive member is exposed from the light reflective member.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No.2017-162274, filed on Aug. 25, 2017, the disclosure of which is herebyincorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a light emitting device and method ofmanufacturing the same.

Japanese Unexamined Patent Application Publication No. 2016-48718discloses a light emitting device a side-emission type light emittingdevice including: a flip-chip type light emitting element in which anelement substrate, a crystal layer on the element substrate, outerelectrodes electrically connected to the crystal layer are included; anoptical member having a surface inclined to the outer electrodes, theoptical member formed on the element substrate side of the lightemitting element; a reflective layer formed on the inclined surface ofthe optical member. In such light emitting device, light emitted fromthe light emitting element and entering the optical member is reflectedby the reflective member, and extracted from the light extractionsurface of the optical member.

SUMMARY

The light emitting device disclosed in the above mentioned publicationhas a poor light emission efficiency due to a poor efficiency of lightincident from the light emitting element to the optical member. In orderto increase the light output, the light emitting element is needed to belarger, resulting in increase of the size of the light emitting device.

Certain embodiment of the present disclosure is intended to provide aside-emission type light emitting device with good emission efficiency.

A light emitting device according to certain embodiment of the presentdisclosure includes a light emitting element, a light transmissivemember, a light guide member, and a light reflective member. The lighttransmissive member is disposed on an upper surface of the lightemitting element, and has a lower surface including a first regionfacing the light emitting element and a second region positioned outsideof the first region. The light guide member covers a lateral surface ofthe light emitting element and the second region of the lower surface ofthe light transmissive member. The light reflective member covers thelight emitting element, an upper surface of the light transmissivemember, and the light guide member. One of lateral surfaces of the lighttransmissive member is exposed from the light reflective member.

A method of manufacturing a light emitting device according to certainembodiment of the present disclosure includes: disposing a plurality oflight emitting elements separated from each other; disposing a lighttransmissive member over adjacent two of the light emitting elements;disposing a light guide member covering lateral surfaces of the adjacenttwo of the light emitting elements, and a part of a lower surface of thelight transmissive member; disposing a light reflective member coveringthe adjacent two of the light emitting elements, an upper surface of thelight transmissive member, and the light guide member; and cutting thelight guide member and the light reflective member between the adjacenttwo light emitting elements.

A method of manufacturing a light emitting device according to certainembodiment of the present disclosure includes: providing two lightemitting elements disposed on a first surface of a light transmissivemember; disposing a light guide member covering a part of the firstsurface of the light transmissive member, and lateral surfaces of thetwo light emitting elements; disposing a light reflective membercovering the two light emitting elements, a second surface of the lighttransmissive member, and the light guide member; cutting the lighttransmissive member and the light reflective member between the twolight emitting elements.

The light emitting device and the method of manufacturing the lightemitting device according to certain embodiment of the presentdisclosure can realize a light emitting device with good emissionefficiency.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of a light emitting device ofEmbodiment 1.

FIG. 2 is a schematic sectional view of the light emitting device takenalong a line II-II in FIG. 1.

FIG. 3 is a schematic sectional view of a light emitting device ofanother embodiment.

FIG. 4A is a schematic sectional diagram showing a process of anembodiment of a method of manufacturing a light emitting device.

FIG. 4B is a schematic sectional diagram showing a process of theembodiment of the method of manufacturing the light emitting device.

FIG. 4C is a schematic sectional diagram showing a process of theembodiment of the method of manufacturing the light emitting device.

FIG. 4D is a schematic sectional diagram showing a process of theembodiment of the method of manufacturing the light emitting device.

FIG. 4E is a schematic sectional diagram showing a process of theembodiment of the method of manufacturing the light emitting device.

FIG. 5A is a schematic sectional diagram showing a process of a secondembodiment of a method of manufacturing a light emitting device.

FIG. 5B is a schematic sectional diagram showing a process of the secondembodiment of the method of manufacturing the light emitting device.

FIG. 5C is a schematic sectional diagram showing a process of the secondembodiment of the method of manufacturing the light emitting device.

FIG. 5D is a schematic sectional diagram showing a process of the secondembodiment of the method of manufacturing the light emitting device.

FIG. 5E is a schematic sectional diagram showing a process of the secondembodiment of the method of manufacturing the light emitting device.

DETAILED DESCRIPTION

Hereinafter, an embodiment will be appropriately described referring todrawings. However, a light-emitting device described below is providedfor the purpose of embodying the technical concept described in thepresent disclosure, and unless specifically stated otherwise, thepresent disclosure is not limited to descriptions below. Also, thecontent of one embodiment and example can be applied to otherembodiments and examples. There is a case where a magnitude, aspectratio or positional relation of members illustrated in each drawing isexaggerated so as to clarify the description.

In FIGS. 1 to 3, an X direction, a Y direction and a Z directionperpendicular to one another are illustrated with allows. The presentdisclosure may refer to the X direction as a longitudinal direction, theY direction as a thickness direction, the Z direction as a widthdirection.

The light emitting device has a rectangular-cuboid outer shape and hassix outer surfaces including an upper surface, a tower surface which isopposite to the upper surface and serves as a mounting surface, fourlateral surfaces between the upper surface and the lower surface. One ofthe lateral surfaces is configured with one surface of the lighttransmissive member exposed from the light emitting device. The surfaceof the light transmissive member exposed from the light emitting deviceserves as a light extraction surface, and referred to as a front surfacein which the surface of the light transmissive member is included. Asurface opposite to the front surface is also referred to as a backsurface.

The term “downsizing” in the present disclosure means reducing the sizeof the light emitting device or the components thereof. Specifically,“thinning” means reducing the length in the thickness direction of thelight emitting device. “Narrowed” means reducing the length in the widthdirection at the light emitting device.

FIG. 1 shows a front view of the light emitting device 100 in accordancewith Embodiment 1 of the present disclosure. FIG. 2 shows a sectionalview of the light emitting device taken along a line II-II in FIG. 1.

The light emitting device 100 according to certain embodiment includes alight emitting element 10, a light transmissive member 12, a light guidemember 11, and a light reflective member 13.

The light transmissive member 12 is positioned on an upper surface 10 uof the light emitting element 10 and the light guide member 11. A lowersurface 20 of the light transmissive member 12 is configured with afirst region 22 and the second region 24.

The light guide member 11 covers the lateral surfaces 21 of the lightemitting element 10 and the second region 24 of the light transmissivemember 12. The light reflective member 13 covers outer surfaces 25 ofthe light guide member 11, part of the lower surface 10 b and part ofthe lateral surfaces of the light emitting element 10. The lightreflective member 13 covers the lateral surfaces and the upper surfaceof the light transmissive member 12 except for the light extractionsurface 18.

Light emitted from the upper surface 10 u of the light emitting element10 enters from the first region 22 of the light transmissive member 12to the inside of the light transmissive member 12. Light emitted fromthe lateral surfaces 21 of the light emitting element 10 enters into theinside of the light guide member 11, followed by entering into the lighttransmissive member 12 from the second region 24. With this structure,the light guide member 11 covers the lateral surfaces 22 of the lightemitting element 10 and the second region 24 of the light transmissivemember 12. This allows light emitted from the lateral surfaces 21 toenter into the light transmissive member 12. Accordingly, the light fromthe light emitting element 11) can be efficiently enter into the lighttransmissive member 12 with less loss. A light emitting device with goodemission efficiency can be obtained without increasing the size of thelight emitting element 10.

The following describes a preferable embodiment of the light emittingdevice 100.

As shown in FIGS. 1 and 2, the light emitting device 100 according tocertain embodiment includes a light emitting element 10 in which a lighttransmissive substrate 14, a semiconductor layered body 15, and a pairof electrodes 16 formed on a lower surface 10 b of the semiconductorlayered body 15 are included. A shape of an upper surface 10 u of thelight emitting element 10 can be appropriately selected, however, aquadrangular is preferable, or rectangular is more preferable. In thecase where the upper surface 10 u has a rectangular shape, a ratio of alength in the longitudinal direction to a length in the width directionis preferably 1.2 to 20, or 3 to 10 is more preferable. Specifically,the light emitting element 10 has a length in the longitudinal directionof from 200 μm to 2000 μm, a length in the thickness direction of from10 μm to 300 μm, and a length in the width direction of from 100 μm to500 μm. More preferably, a length in the longitudinal direction is from500 μm to 1500 μm, a length in the thickness direction is 50 μm to 200μm, and a length in the width direction is 100 μm to 400 μm. With thisstructure, the light emitting device 100 can be downsized, and lightemitted from the upper surface 10 u and the lateral surfaces 21 of thelight emitting element 10 can be efficiently extracted to outside.

The light transmissive member 12 is disposed on the light emittingelement 10 and the light guide member 11 to extract light, which hasentered from the upper surface 10 u of the light emitting element 10 andthe light guide member 11, to outside from the light extraction surface18.

In the light emitting device 100 according to the present embodiment,the light transmissive member 12 has a smaller area than the area of thelight emitting element 10 in a top view. As shown in FIG. 2, the lateralsurfaces 21 of the light emitting element 10 is positioned inner sidethan the lateral surfaces of the light transmissive member 12.

Positioning the lateral surfaces 21 of the light emitting element 10inner side than the lateral surfaces of the light transmissive member 12can have the second region 24. Having the second region 24 of the lighttransmissive member 12 allows the light guide member 11 to cover thesecond region 24. Accordingly, light entering from the lateral surfaces21 of the light emitting element 10 to the light guide member 11 canefficiently enter the light transmissive member 12.

Preferably, the light transmissive member 12 is disposed on the lightemitting element 10 such that the center in the X direction of the lightemitting element 10 substantially coincides with the center in the Xdirection of the light transmissive member 12 along the Y direction in afront view. With this structure, light emitted from the light emittingelement 10 can uniformly enter into the lower surface of the lighttransmissive member 12, thereby improving color non-uniformity. Thelight transmissive member 12 can be disposed on the light emittingelement 10 such that the center in the Z direction of the light emittingelement 10 substantially coincides with the center in the Z direction ofthe light transmissive member 12 along the Y direction in a sectionalview, however, the positioning is not limited thereto. The center of thelight transmissive member 12 can be positioned closer to the frontsurface or back surface than the center of the light emitting element10. In other words, the light transmissive member 12 can be disposed onthe light emitting element 10 such that the second region 24 can beprovided in the front surface side and the back surface side.

The shape of the light transmissive member 12 in a front view can beappropriately selected, for example, substantially trapezoidal,substantially circular, or substantially semiellipsoidal shape, orsubstantially rectangular shape as shown in FIG. 1. The shape of thelight transmissive member 12 in a sectional view can be appropriatelyselected, for example, substantially rectangular shape as shown in FIG.2, but preferably a shape whose back surface has an inclined or curvedsurface broadening from the upper surface side to the lower surfaceside.

The light guide member 11 covers the lateral surfaces 21 of the lightemitting element 10 to guide light emitted from the lateral surfaces 21to the light transmissive member 12. Providing the light guide member 11can reduce that light reached from the inside of the light emittingelement 10 to the lateral surfaces 21 of the light emitting element 10reflect at the lateral surface 21, thereby extracting the light tooutside the light emitting element 10. Accordingly, the light guidemember 11 allows the light emitted from the lateral surface 21 of thelight emitting element 10 to be guided to the light transmissive member12, thereby enhancing emission efficiency of the light emitting device100.

The light guide member 11 can have a shape appropriately selected, orexample, the outer surfaces 25 in FIG. 2 can each have a flat in curvedsurface. The “curved surface” here means a curved surface convex towardthe light reflective member 13, or a curved surface convex toward thelight emitting element 10. Shapes of the front surface and the backsurface of the light guide member 11 can be the same or a different fromeach other. As shown in FIG. 2, in the light emitting device 100according to certain embodiment, the outer surfaces 25 of the lightguide member 11 respectively have inclined surfaces outwardly extendingfrom the lateral surfaces of the light emitting elements 10 toward outeredges of the light transmissive member 12. In the case of the curvedsurface convex toward the light reflective member 13, an effect of thelight guide member 11 can be significantly obtained. Accordingly, lightentering from the lateral surfaces 21 of the light emitting element 10into the light guide member 11 can effectively enter the lighttransmissive member 12 through the second region 24.

As shown in FIGS. 1 and 2, the light guide member 11 in the lightemitting device 100 according to certain embodiment covers at least 50%of the lateral surfaces 21 of the light emitting element 10, and atleast 50% of the second region 24 of the light transmissive member 12.The light guide member 11 preferably cover at least 70% of the lateralsurfaces 21 of the light emitting element 10 and the second region 24 ofthe light transmissive member 12. Covering most of the part of thelateral surfaces 21 and the second region 24 allows the light emittedfrom the lateral surface 21 of the light emitting element 10 toefficiently enter into the light guide member 11, thereby enhancingemission efficiency of the light emitting device 100.

As shown in FIG. 2, in the light emitting device 100 according tocertain embodiment, a light guide member 11 positioned closer to thefront surface 38 of the light emitting device 100 is preferably formedhaving a certain distance from the front surface 38. In other words, thelight reflective member 13 preferably covers periphery of the secondregion 24 closer to the front surface 38. With this structure, lightentering from the lateral surfaces 21 of the light emitting element 10to the guide member 11 a is less likely to enter the light transmissivemember 12, thereby alleviating the light to exit from the front surface38 of the light emitting device 100. This can reduce an occurrence ofcolor non-uniformity of the light emitting device 100. The “certaindistance” herein means the distance with which light is less likely topass through. The “certain distance” can be appropriately selecteddepending on the size of the light emitting device or the configurationof the light emitting element.

On the other hand, a light guide member 11 b positioned closer to theback side preferably covers the second region 24 in wider area. Forexample, center of the light transmissive member 12 in the Z directionpreferably substantially coincides with the center of the light emittingelement 10 or closer to the back side surface than the center thereof.The light guide member 11 b on the back surface side also preferablycovers the second region 24 in wider area than that the light guidemember 11 a on the front surface 38 side does. More preferably, thelight member 11 b entirely covers the second region 24 close to the backsurface. This allows light emitted from the lateral surfaces 21 of thelight emitting element 10 to be efficiently taken into the light guidemember 11 b, thereby increasing emission efficiency.

As shown in FIG. 1, preferably, the light guide member 11 on the lateralsurface side of the light emitting device 100 entirely covers thelateral surfaces 21 of the light emitting element 10 and the region 24of the light transmissive member 12. This allows light emitted from thelateral surfaces 21 of the light emitting element 10 to be efficientlytaken into the light guide member 11, thereby increasing emissionefficiency. As shown in FIG. 1, the light transmissive member 12 ispreferably disposed on the light emitting element 10 such that thecenter in the X direction of the light emitting element 10 substantiallycoincides with the center in the X direction of the light transmissivemember 12 along the Y direction, and the light guide member 11 ispreferably provided such that shapes and covering surface areas aresubstantially the same on both of right-side and left-side lateralsurfaces. Accordingly, the light entering from the lateral surfaces 21of the light emitting element 10 to the light guide member 11 uniformlyenters into lateral surfaces in right-side and left-side of the lighttransmissive member 12, and exits from the light extraction surface 18of the light transmissive member 12 uniformly in right-side andleft-side, resulting the light emitting device with improved colornon-uniformity.

In the light emitting device 100 according to certain embodiment, thefront surface 38 and the lower surface of the light emitting device 100define an angle of from 80° to 100°. This can alleviate generation ofgap between the light guide plate and the light extraction surface 18after a light guide plate for backlight is disposed on the lightextraction surface 18, and light exiting from the light extractionsurface 18 can efficiently enter the light guide plate, therebyrealizing a backlight with good emission efficiency.

The light reflective member 13 covers part of the lower surface 10 b andthe lateral surfaces 21 of the light emitting element 10 that are notcovered by the light guide member 11. With this structure, light that isemitted from the lower surface 10 b and the lateral surfaces 21 of thelight emitting element 10 and does not enter into the light guide member11, can be reflected by the light reflective member 13 to enter thelight transmissive member 12. The light reflective member 13 covers theouter surfaces 25 of the light guide member 11, therefore, lightentering from the latera surfaces 21 of the light emitting element 10into the light guide member 11 can be reflected by the light reflectivemember 13, and guided to the light transmissive member 12 to obtain thelight emitting device 100 with good emission efficiency.

The light reflective member 1 covers an timer surface of the lighttransmissive member 12, lateral surfaces except for the light extractionsurface 18 of the light transmissive member 12, and part of the secondregion 24 that is not covered by the light guide member 11. This canrealize a light emitting device with good contrast, in other words, gooddistinguishability between a light emitting region and anon-light-emitting region.

Modification

A shown in FIG. 3, the light emitting device 200 do not include basemember. Other than this, the light emitting device 200 is substantiallythe same as or a similar to the foregoing embodiment. The light emittingdevice 200 can have even more reduced thickness because it does not havea base member.

Method of Manufacturing Light Emitting Device

The following describes a method of manufacturing a light emittingdevice according to the present disclosure referring to the drawings.The same terms are used for components before and after curing orcutting.

First Method Manufacturing Light Emitting Device

The method of manufacturing the light emitting device 100 includes:disposing a plurality of light emitting elements separated from eachother; disposing a light transmissive member over adjacent two of thelight emitting elements; disposing a light guide member covering lateralsurfaces of the adjacent two light emitting elements, and part of alower surface of the light transmissive member; disposing a lightreflective member covering the adjacent two light emitting elements, anupper surface of the light transmissive member, and the light guidemember; and cutting the light member and the light reflective memberbetween the adjacent two light emitting elements.

With this manufacturing method, the light emitting device 100, in whichlight emitted from the lateral surfaces 21 of the light emittingelements 10 enter into the light guide member 11, and is reflected bythe light reflective member 13, and is eventually extracted from a lightextraction surface 18 of the light transmissive member 12. The lightemitting device 100 manufactured by this method can have a good emissionefficiency.

1-1. Disposing Light Emitting Element on Base Member

As shown in FIG. 4A, electrodes 16 of the light emitting elements areprovided such that the electrodes 16 face the mounting board while thelight emitting elements 10 are separated from each other, and are bondedto the base member. Examples of techniques for the bonding include AuSnbonding, solder bonding, Au-bump bonding, con-bump bonding, or bondingusing electrically-conductive adhesives, anisotropic conductive pasts,or a anisotropic conductive films. Specifically, AuSn bonding is themost suitable technique from a standpoint of the connection stability orreliability of the connection portion for the timing of the secondarymounting or operation. The interval between the adjacent light emittingelements 10 can be appropriately selected, however, preferably 30 μm to300 μm, more preferably 50 μm to 150 μm at the light extraction surface18 side, from a standpoint of the size of the light emitting devices 100and number of the light emitting devices which can be manufactured fromone base member block.

1-2. Providing Light Transmissive Member 12

In the present embodiment, at least one light transmissive member 12having a sheet shape is provided. The light transmissive member extendsin a longitudinal direction and a width direction in a plan view. Thetight transmissive member 12 having the sheet shape can be formed using,for example, a wavelength conversion member formed using a liquid resin,and as necessary, a phosphor is mixed therewith, by coating, compressionmolding, transfer molding, injection molding, splaying, printing,potting, or the like. Alternatively, a fluorescent material formed in asubstantially uniform thickness by electrophoretic deposition or thelike can be impregnated with a resin to form the light-transmissivemember 12. The surface of the light transmissive member 12 can be a flatsurface or rough surface. The rough surface can be easily formed, forexample, by compression molding, transfer molding, or injection molding.The roughness formed on the surface can enhance adhesion between thelight transmissive member 12 and the light reflective member 13, therebyimproving reliability of the light emitting device. End surface of thelight transmissive member 12 can be an inclined surface or curvedsurface broadening from the upper surface side to the lower surfaceside. Having an inclined surface on the back surface of the lighttransmissive member 12 which is opposite to the light extraction surface18 an further increase emission efficiency.

The light transmissive member 12 should have a size capable of beingdisposed over the adjacent two light emitting elements 10 on the basemember 17. The adjacent light transmissive member 12 can be separated ina predetermined interval. The interval of the adjacent lighttransmissive members 12 can be appropriately selected, however, in viewof the size of the light emitting device and singulation of the lightemitting device, the interval between surfaces of the adjacent lighttransmissive members 12 facing each other is preferably 30 μm to 300 μm,more preferably 50 μm to 150 μm.

1-3. Disposing Liquid Resin Material

Although not shown in the drawings, resin material for forming the lightguide member 11 is disposed on the light transmissive substrate 14 ofthe light emitting elements 10 mounted on the base member. To disposethe resin material for forming the light guide member 11, for example,the light transmissive substrate 14 of the light emitting elements 10 isbrought into contact with resin adjusted in a certain thickness bydispensing, transferring with pin, or using a squeegee. This techniqueis called dipping. The amount of the liquid resin to be disposed can beappropriately selected, however it is preferably adjusted in sufficientamount to cover the lateral surfaces 21 of the light emitting elements10, and to form inclined surfaces respectively connecting the lateralsurfaces 21 of the light emitting element 10 and the second region 24 ofthe light transmissive member 12.

1-4. Disposing Light Transmissive Member 12 and Forming Light GuideMember 11

As shown in FIG. 4B, the light transmissive members 12 are disposed overthe adjacent two light emitting elements 10. At this timing, as shown inFIG. 4D, the liquid resin material disposed on the light emittingelements 10 is pushed out from the regions between the light emittingelements 10 and the light transmissive member 12. The pushed out liquidresin material covers the lateral surfaces 21 of the light emittingelements 10 and the second region 24 of the light transmissive member12, and forms the light guide member 11 having the inclined surfaceconnecting the lateral surfaces 21 of the light emitting element 10 andthe second region 24.

Thereafter, the liquid resin material is cured by heat or ultraviolet tobond the light emitting elements 10 and the light transmissive member 12while fixing the shape of the inclined surface of the light guide member11. Curing of the light guide member 11 can be performed, for example,by heating for 4 hours with an oven set at 150° C.

When the light transmissive member 12 is disposed on the light emittingelement 10, the liquid resin material can be remained in the lighttransmissive member 12 and the light emitting elements 10. With thisstructure, light emitted from the upper surface 10 u of the lightemitting elements 10 can be uniform in the cured liquid resin materialbefore entering into the light transmissive member 12, thereby improvingcolor non-uniformity of the light emitted from the light emittingdevice.

1-5. Forming Light Transmissive Member

In the present disclosure, the outline of the light transmissive member12 having a sheet shape can be formed in a slightly larger size, andafter being disposed on the light emitting elements 10, part of outeredges of the light transmissive member 12 can be removed to adjust itsshape. This can reduce variance of the shape of the light transmissivemember 12 in forming, or of positioning thereof in disposing. Thevariance of the shape or positioning of the light transmissive member 12may cause reduction in the thickness of the light reflective member 13covering herein. This may cause insufficient light blocking, and thelight leakage from the area other than the light extraction surface 18of the light emitting device 100. Specifically, when the lighttransmissive member 12 contains one or more phosphors, light leakagefrom areas other than the light extraction surface 18 may cause colorshift. The light emitting device according to the present embodiment canreduce a possibility of such insufficient light blocking, light leakage,and color shift.

Accordingly, the target value or the design value of the thickness ofthe light reflective member 13 can be smaller, in other words, thisforming step can reduce the thickness of the light reflective member 13including margin which is remained to take into account manufacturingvariance, the reducing the thickness of the light emitting device.

Examples of methods of the forming include dicing, process using Thomsonblade, laser processing. Among these examples, dicing is preferablebecause it can accurately term the shape.

1-6. Forming Light Reflective Member 13

Subsequently, as shown in FIG. 4D, the light reflective member 13 isformed to cover the light transmissive member 12, the light emittingelement 10, light guide member 11, and the base member 17. Forming thelight reflective member 13 can be performed, for example, by printing,potting or molding such as compression molding, transfer molding, orinjection molding. Concentration of filler contained in the resin in thelight reflective member 13 is high, the fluidity of the light reflectivemember 13 is reduced. Therefore, compression molding and transfermolding are especially suitable.

1-7. Singulating

Subsequently, as shown in FIG. 4E, singulating is performed between theadjacent two light emitting elements 10 to obtain a plurality of lightemitting device. The light reflective member 13 and the base member 17are cut between adjacent two light transmissive members 12. The lightreflective member 13, the light transmissive member 12, and the basemember 17 are cut between the light emitting elements 10 on which thelight transmissive member 12 straddles. The cut surface of the lighttransmissive member 12 becomes the light extraction surface 18 of thelight emitting device 100.

Example methods of the cutting include dicing, processing using Thomsonblade, laser processing. At the timing of the cutting, employing a pointas the reference point used to form the light transmissive member 12 canrealize accurate thinning by cutting the light reflective member 13,specifically, by cutting the back surface side of the light reflectivemember 13 which is opposite side of the light extraction surface 18.Thus, the light emitting device can be downsized.

The steps of the first method of the manufacturing are described abovein sequence however, the manufacturing steps do not necessarily beperformed in this order. Some of the steps can be performed at the sametime, for example, the step 1-2. Providing Light Transmissive Member and1-3. Disposing Liquid Resin Material can be performed at the same time.

Second Method of Manufacturing Light Emitting Device

The second method of the manufacturing a light emitting device includes:disposing a light guide member covering part of a lower surface of thelight transmissive member and the lateral surfaces of adjacent two lightemitting elements disposed on a lower surface of a light transmissivemember, the lower surface of the light transmissive member being asurface on which the light emitting elements are disposed; disposing alight reflective member covering an upper surface of the lighttransmissive member and the adjacent two light emitting elements, theupper surface of the light transmissive member being opposite to thelower surface thereof; and cutting the light transmissive member and thelight reflective member between the adjacent two light emittingelements.

The second method of manufacturing differ from the first method ofmanufacturing in that the second method can produce a light emittingdevice in which the base member 17 is not included.

In the second method of manufacturing, the upper surface and the lowersurface of the light transmissive member 12 refers the upper surface andthe lower surface of the light transmissive member 12 as shown in theposition of FIGS. 5D and 5E.

2-1. Mounting Light Emitting Element 10

As shown in FIG. 5A, ale light transmissive member 12 having a sleetshape is provided. Subsequently, liquid resin material for forming thelight guide member 11 is disposed on the lower surface of the lighttransmissive member 12. Disposing method and disposing amount of theliquid resin material are the same as that of the first method ofmanufacturing. As shown in FIG. 5B, a plurality of light emittingelements 10 on the light transmissive member 12 via the liquid resinmaterial. At this timing, the liquid resin material disposed on thelight transmissive member 12 is pushed out from the region between thelight emitting elements 10 and the light transmissive member 12, andform inclined surfaces respectively connecting lateral surfaces 21 ofthe light emitting elements 10 and a second region 24 of the lighttransmissive member 12. Thereafter, the light guide member 11 is curedby the method described in the step 1-5. Forming Light TransmissiveMember of the first method.

2-2. Cutting Light Transmissive Member 12

As shown in FIG. 5C, the light transmissive member 12 is cut such thattwo light emitting elements 10 are disposed on one light transmissivemember 12. The cutting can be performed, for example, by dicing,processing using Thomson blade, laser processing.

In the second method of manufacturing, the light transmissive member 12is cut every two light emitting elements 10 after disposing the lightemitting elements 10 on the light transmissive member 12, however, themethod of the manufacturing is not limited thereto. For example, thetransmissive member 12 can be cut into pieces which are large enough toallow two light emitting elements 10 to be disposed, followed bydisposing the light emitting elements 10.

2-3. Forming Light Reflective Member 13

Subsequently, as shown in FIG. 5D, the workpieces are transferred on atransfer sheet 27 such that electrodes 10 of the light emitting elements10 face the transfer sheet 27. Then the light reflective member 13 isformed to cover the light emitting elements 10, the light transmissivemember 12, and the light guide member 11. The light reflective member 13is preferably formed by the same method as those described in the step1-7. Singulating.

The transfer sheet 27 can be formed using, for example, resin film,metal board, ceramic board as a single component, or composite memberthereof. The transfer sheet 27 can be a rigid sheet or flexible sheet.The transfer sheet 27 is removed after the light emitting device ismanufactured by the series of manufacturing steps.

Instead of transferring the workpieces on the transfer sheet 27 suchthat the electrodes 16 of the light emitting elements 10 face thetransfer sheet 27, transferring can be performed by disposing theworkpieces after the step 2-2. Cutting Light Transmissive Member 12 onthe transfer sheet 27 such that the upper surface of the lighttransmissive member 12 faces the transfer sheet 27. Thereafter the lightreflective member 13 can be formed to cover the light emitting elements10, the light transmissive member 12, and the light guide member 11 suchthat part of each of the electrodes 10 is exposed.

2-4. Singulating

Subsequently, as shown in FIG. 5E, the workpieces are cut between theadjacent two light emitting elements 10 to obtain a plurality of lightemitting device. In the case where the light transmissive member 12 doesnot straddle two light emitting elements 10, the light reflective member13 is cut between the light emitting elements 10. In the case where thelight transmissive member 12 straddles two light emitting elements 10,the light reflective member 13 and the light transmissive member 12 arecut between the two light emitting elements 10. A cut surface of thelight transmissive member 12 serves as a light extraction surface 18 ofthe light emitting device. The cutting can be performed by the same or asimilar method used in the step 1-7. Singulating. After the singulation,the transfer sheet 27 can be removed.

The steps of the second method of the manufacturing is described abovein sequence, however, the manufacturing steps do not necessarily beperformed in this order. Far example, the order of the steps can bechanged, or some of the steps can concurrently be performed. Except forthe steps described in the second method of manufacturing, themanufacturing method is the same as that of the first method ofmanufacturing. In the second method of manufacturing, a base member isnot required, thereby enabling production of the light emitting devicewith reduced thickness.

The following describes the components of a light-emitting deviceaccording to embodiments of the present disclosure.

Light Emitting Element 10

The light emitting element is preferably a semiconductor light emittingelement. An example of the semiconductor light emitting element includesa light emitting diode (LED) chip. The semiconductor light emittingelement can include a semiconductor layered body including at leastlight omitting structure and a pair of electrodes, and can furtherinclude a light transmissive substrate. The light emitting elementpreferably includes a positive (p) and negative (n) electrodes on thesame surface. The light emitting element is a flip-chip (i.e., facedown) mounting type, the primary emission surface is opposite to thesurface on which the electrodes are formed.

Semiconductor Layered Body 15

The semiconductor layered body preferably includes at least an n-typesemiconductor layer, a p-type semiconductor layer, and the active layerinterposed therebetween. For the semiconductor material, nitridesemiconductor capable of efficiently emitting light having a shortwavelength which readily excites fluorescent substance. An example of atypical nitride semiconductor is one that is represented byIn_(x)Al_(Y)Ga_(1-X-Y)N (0≤X, 0≤Y, X+Y≤1). Alternative examples includezinc sulfide, zinc selenide, and silicon carbide.

Light Transmissive Substrate 14

For the light transmissive substrate, a growth substrate allowingepitaxial growth of the semiconductor layer. Examples of the lighttransmissive substrate include an insulating substrate such as sapphire(Al₂O₃) or spinel (MgAl₂O₄), and a nitride-based semiconductorsubstrate. In the case where the light transmissive substrate 14 havinglight transmissivity such as sapphire substrate is employed for a growthsubstrate of the semiconductor layer, the light transmissive substrate14 can be included in the light emitting device without being removed.

The light transmissive substrate can have surface roughness including aplurality of recesses and protrusions on the surface.

Electrodes 16, 16 a, 16 b

The electrodes can be formed using pieces of metal or metal alloy. Forexample, at least one kind of materials selected from the groupconsisting of gold, silver, copper, iron, tin, platinum, rhodium, titan,nickel, paradigm, aluminum, tungsten, chromium, molybdenum, and alloythereof. Among these examples, copper is preferable due to its goodthermal conductivity and relatively low cost. Gold or a gold alloy isalso preferable, because it has a good bondability due to the propertiesthat is chemically stable and is less likely to undergo surfaceoxidation. The electrodes can have a film formed of gold or silver onthe surface thereof in view of the solder bondability.

Light Transmissive Member 12

The light transmissive member includes a light transmissive material.Examples of the light transmissive materials include light transmissiveresins and glass. Specifically, light transmissive resins arepreferable, for example, thermosetting resins such as silicone resins,modified silicone resins, epoxy resins, and phenol resins; orthermoplastic resins such as polycarbonate resins, acrylic resins,methylpentene resins, or polynorbornene resins. Specifically, siliconeresins are suitable because it has good heat and light resistance.

The light transmissive member can contain various types of fillers forthe purpose of adjusting the viscosity, or the like.

The light transmissive member can be a wavelength conversion member inwhich at least one phosphor in addition to the light transmissivematerial. The phosphor can be that is capable of excitation by lightfrom the light emitting element. Examples of the phosphor capable ofexcitation by blue light emitting elements or ultraviolet light elementsinclude: cerium-activated yttrium aluminum garnet (Ce:YAG)-basedphosphors; cerium-activated lutetium aluminum garnet (Ce:LAG-basedphosphors; europium and/or chromium-activated nitride-containing calciumaluminosilicate (CaO.Al₂O₃.SiO₂)-based phosphors; europium-activatedsilicate ((Sr,Ba)₂SiO₄)-based phosphors; nitride-based phosphors such asβ-SiAlON phosphors, CASN-based phosphors or SCASN-based phosphors;KSF-based phosphors (K₂SiF₆:Mn); sulfide-based phosphors; quantum dot;and the like. Combining such phosphors and the blue light emittingelement or ultraviolet light emitting element can realize production ofa light emitting device, that emit light of various colors (e.g.,white-color based light emitting device).

The wavelength conversion member can contain various types of fillersfor the purpose of adjusting the viscosity, or the like.

The light transmissive member 12 can be single layer or multilayerstacked in the thickness direction. In the case of the lighttransmissive member configured by multilayer, different types of basematerial can be used in the respective layers, or different types offluorescent substances can be used in the respective layers. Theoutermost layer can be a layer free of the fluorescent substances,thereby alleviating degradation of the fluorescent substances due to,for example, external air.

Light Guide Member 11, 11 a, 11 b

The light guide member can be formed using a liquid resin material thathas light transmissivity, is capable of guiding of light emitted fromthe light emitting element, and is capable of bonding the light emittingelement and the light transmissive member. The liquid resin material ispreferably a material that is a liquid state before being cured, andcapable of bonding by curing. A base material of the liquid resinmaterial can be at least one kind of materials selected from the groupconsisting of a silicone resin, an epoxy resin, a phenol resin, apolynorbornene resin, an acrylic resin, or modified resins thereof.Among these examples, silicone resins or modified silicone resins arepreferable due to good heat and light resistant. Specific examples ofsilicone resins include dimethyl silicone resin, phenylmethyl siliconeresin, and diphenyl silicone resins.

For example, various types of fillers can be added in the light guidemember in order to adjust the refractive index of the light guidemember, or to adjust the viscosity of the uncured light guide member(i.e., the liquid resin material).

Light Reflective Member 13

The light reflective member 13 cab be formed using a light reflectiveresin. The light reflective resin preferably has at least 70%, morepreferably at least 80%, even more preferably at least 90% ofreflectance to the peak emission wavelength of light emitted from thelight emitting element. Light reaching the light reflective member isreflected to the light reflective member, and travels toward the lightextraction surface of the light emitting device, thereby increasinglight extraction efficiency of the light emitting device.

The light transmissive member can be, for example, a light transmissiveresin in which light reflective substances are dispersed. Examples ofthe light reflective substances include titanium oxide, silicon dioxide,zirconium dioxide, potassium titanate, alumina, aluminum nitride, boronnitride, mullite, and the like. Particle of the light reflectivesubstances can have granular, fiber, or flake shape. The particleshaving fiber shapes is preferable because it can be expected that alight reflective substances having a fiber shape can have a low thermalexpansion rate

Particularly preferable examples of materials usable for the lightreflective member include thermosetting resins such as silicone resin,modified silicone resin, epoxy resin, phenol resin.

Base Member 17

The base member can be one that includes a leadframe configured withpairs of metal plate, at least a base, and pairs of connection terminalscorresponding to the positive and negative terminals disposed on thebase. In the case of employing a base member, the connection terminalsare usually on a first main surface of the base. The first main surfacehere means one of the main surfaces of the base or the base member. Theshape of the base member is not specifically limited, however, it can bethe shape corresponding to the shape of the base described below. Forexample, preferably at least the first main surface preferably extendsin the longitudinal direction, and more preferably the base member has awidth perpendicular to the longitudinal direction.

Base

The base can be formed by materials appropriately selected. Examples ofmaterials of the base include metals, ceramics, resins, dielectricmaterials, pulp, glass, paper, composite materials thereof, or compositematerials thereof with electrical conductive materials such as metal,carbon. Examples of metals include copper, iron, nickel, chromium,aluminum, silver, gold, titanium, or alloys containing thereof. Examplesof resins include epoxy resins, bismaleimide triazine (BT) resins,polyimide resins. Resin materials can contain white pigment such astitanium oxide. Among these examples, ceramics or composite resins arepreferable.

Examples of the ceramic include aluminum oxide, aluminum nitride,zirconium oxide, zirconium nitride, titanium oxide, titanium nitride,and mixtures of these ceramic materials. Among these examples, aluminumnitride is preferable due to its good heat dissipation. As a compositeresin, glass-epoxy resin is preferably used. The base can be one thathas an appropriate mechanical strength, or has a flexibility.

The “light transmissive/transmissivity” here refers to a transmittanceof preferably 60% or higher, more preferably 70% or higher, even morepreferably 80% or higher for the peak emission wavelength of the lightemitting element.

Certain embodiments of the present disclosure are described above asexamples. It is, however, expressly noted that the present invention isnot limited to these embodiments, but the principles of the presentinvention defined herein can be applied to other embodiments andapplications without departing from the spirit and scope of theinvention.

What is claimed is:
 1. A light emitting device comprising: a lightemitting element; a light transmissive member disposed on an uppersurface of the light emitting element, the light transmissive memberhaving a lower surface including a first region facing the lightemitting element and a second region positioned outside of the firstregion; a light guide member covering a lateral surface of the lightemitting element and the second region of the lower surface of the lighttransmissive member; and a light reflective member covering the lightemitting element, an upper surface of the light transmissive member, andthe light guide member, wherein one of lateral surfaces of the lighttransmissive member is exposed from the light reflective with the restof the lateral surfaces of the light transmissive member being coveredby the light reflective member.
 2. The light emitting device accordingto claim 1, wherein the light guide member has an inclined surfaceextending outward from the lateral surface of the light emitting elementtoward an outer edge of the light transmissive member.
 3. The lightemitting device according to claim 1, wherein the light emitting elementincludes a pair of electrodes on a lower surface of the light emittingelement.
 4. The light emitting device according to claim 1, wherein thelight transmissive member has a larger area than the light emittingelement in a top view.
 5. The light emitting device according to claim1, wherein the light guide member covers at least 50% of the lateralsurface of the light emitting element, and at least 50% of the secondregion.
 6. The light emitting device according to claim 1, wherein thelight emitting element extends in a longitudinal direction and a widthdirection in a top view, and a ratio of a length of a side of the widthdirection to a length of a side of the longitudinal direction is 3 to1.0.
 7. The light emitting device according to claim 1, wherein thelight transmissive member includes at least one type of fluorescentsubstance.
 8. The light emitting device according to claim 1, whereinthe light emitting element is disposed on a base member.
 9. A method ofmanufacturing a light emitting device, comprising: disposing a pluralityof light emitting elements separated from each other; disposing a lighttransmissive member to straddle adjacent two of the light emittingelements; disposing a light guide member covering lateral surfaces ofthe adjacent two of the light emitting elements, and a part of a lowersurface of the light transmissive member; disposing a light reflectivemember covering the adjacent two of the light emitting elements, anupper surface of the light transmissive member, and the light guidemember; and cutting the light reflective member and/or the lighttransmissive member between the adjacent two of the light emittingelements.
 10. The method of manufacturing a light emitting deviceaccording to claim 9, further comprising removing a part of an outeredge of the light transmissive member in a top view, after the disposingof the light transmissive member.
 11. The method of manufacturing alight emitting device according to claim 9, wherein the disposing of thelight emitting elements includes disposing the light emitting elementson a base member so that electrodes formed on a lower surface of each ofthe light emitting elements face the base member.
 12. A method ofmanufacturing a light emitting device, comprising: providing two lightemitting elements disposed on a first surface of a light transmissivemember; disposing a light guide member covering a part of the firstsurface of the light transmissive member, and lateral surfaces of thetwo light emitting elements; disposing a light reflective membercovering the two light emitting elements, a second surface of the lighttransmissive member, and the light guide member, the second surface ofthe light transmissive member being opposite to the first surface; andcutting the light reflective member and/or the light transmissive memberbetween the two light emitting elements.